Xfdesktop gives a segmentation fault if you're using minimized application icons, you've just startx'd, and there's no window manager running yet (or it just hasn't had time to start up yet). I can't post the GDB backtrace unfortunately, but it says the segfault is actually in libxfcegui4, netk_workspace_get_number.
I'm not going to be able to do much with this without a backtrace. Are you running a weird window manager?
I can confirm this bug... I'm using beryl 0.2.1 and I didn't have this bug with 4.4.0. If you tell how to do such a trace, I can try to give you one.
We're not using libnetk anymore, so this shouldn't be a problem.